FLOOD03858

• Designation Number: 298
• County: Boulder
• Community: Unincorporated Boulder County
• Stream Name: St. Vrain Creek
• Basin: South Platte
• Title: Floodplain Information Report - St. Vrain Creek, Boulder County, Colorado
• Date: 8/1/1988
• Designation Date: 5/1/1989
• Floodplain - Doc Type: Floodplain Report/Masterplan

to flooding as the result of the occurrence of a IOO-year flood and
which area thus is so adverse to past, current, or foreseeahll~
construction or land use as to constitute a significant hazard to
puhlic health and safety or to property.

Flood Profile. A graph showing the rela U.Juship of water surf ace elev.,
ation or location, the latter generaJ,ly expressed as distance above
mouth for a stream of water flowing in an open channel. It is
generally drawn to shm" Rurface elev,:ltion for the crest of a specific
flood, hut may be prepared for conditions at a given t~ne or stage,

Xlood Stage.
hanks of
which the

The stage or elevation at which
a stearn or body of water begins
elevation is measured.

overflow of the
in the reach or

natural
e.rea in

Intermediate Regional Flood. A type of flood, including the water surface
elevation and territorial occupat:Lon thereof, which can be E~xpected
to occur at any time in a given are<1 "1'3sed upon recorded historical
precipitation and other valid data, bet: with an average statistical
one percent chance of being equaIled or exceeded during anyone year.
The term is used interchangeably with a one percent flood or IOO-year
flood (see definition for IOO-year fJood).

!.eft Bank. The bank on the left side of " river, stream or ,.,ater C011rse
as the observer looks downstream.

probahiliJ:J.:. The annual chance of occllrrence of specific hvc'rologic
events, such as rainfall over a specified area or peak discharge at a
specified location, expressed in percent, e.g., 5% representing one
chance in 20 of the event occurrfng in allY year or an average
recurrence of once in 20 years.

Recurrence Interval.
flood event will

The average number n f years 1N'i thin v....h:Lch a
be equalled or exceeded.

given

Reference Point. A numbered point j. dent i fying a specific 1 Deat ion for
correlating the data shown in variow::; forms tbroughout the report.

~!3ht llank.
looking

The bank on the right side of a ,:-iver, stream or 1;vater course~,
downstream.

Runoff. The quantity of rainfall ,,,hich
the stream as discharge volume. The
rainfall and runoff represents
interception.

!:.lm..rs over the surfac,~ to enter
rlifference in quantity between
louses to lnftl tration and

~!:ream. Any natural channel or depresr;j,cn through lilhich I.,ater flows
either continuously, intermittently <H' periodic.ally, including any
artificial modification of the natura~ channel or depression.

~atershed. The drainage area situated abolTQ ,(1 specified point on a stream
including the area drainpd by tI'i.hutary stream:;; which enter
the main stream above this point,

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